1. Field of the Invention
The present invention relates generally to a ridge waveguide. More specifically, the present invention relates to a ridge waveguide resistive type feed with a matching transformer within the ridge of the waveguide which matches a standard coaxial transmission line to a ridge waveguide.
2. Description of the Prior Art
Typically, in a simple transition feed for a waveguide the probe does not touch the upper surface and may require additional elements for impedance matching. One such probe design that extends partially into the waveguide is illustrated in U.S. Pat. No. 5,867,073, to Sander Weinreb and Dean Bowyer which issued Feb. 2, 1999. Disclosed in U.S. Pat. No. 5,867,073 is a transition between a waveguide and a transmission line in which a probe portion of the transmission line extends into the waveguide to electrically field couple signals between the waveguide and transmission line. The transmission line includes a substrate having conductors disposed therein to prevent energy from propagating into the substrate from the waveguide. Since the probe is formed as an integral element of the transmission line, direct coupling of the waveguide's signals to the transmission line occurs.
The probe heights of the type illustrated in U.S. Pat. No. 5,867,073 and in other simple probe transition feeds are generally dimensionally sensitive and often impractical in ridge waveguides when the space from the top of the ridge to the top or upper face of the waveguide is relatively small.
Further, conventional probes are often shaped to successfully match the transmission line's impedance. Other prior well known art resistively matched transitions would require an external impedance matching network when the waveguide impedance differs from the coaxial transmission line impedance.
Accordingly there is a need for a relatively compact, simple in design yet highly effective feed which does not require substantial probe shaping and/or an external matching network to impedance match the waveguide to a coaxial transmission line.